Power harvesting circuit employing saturable core transformer

A power harvesting system employs a saturable core transformer having first and second primary windings and a secondary winding. The first primary winding is a high impedance winding with a large number of turns and the second primary winding is a low impedance winding with a small number of turns. The first and second primary windings are connected to a load. A relay is operable in a first state to connect A/C power to the first primary winding and in a second state to connect A/C power to the second primary winding. When A/C power is connected to the first primary winding, a small current flows in the first primary winding which is insufficient to activate the load but sufficient to transfer power to the secondary winding. When A/C power is connected to the second primary winding, a larger current flows in the second primary winding sufficient to activate the load and to transfer power to the secondary winding.